It is desirable to manufacture commutators by injection moulding a base from plastics material and assembling copper segments onto the base and securing them to the base by some means. This method of manufacturing allows the production of a very low cost commutator.
In previous designs the tangs of the copper commutator segments have been designed so that wire is hooked into them and then a welding tool is brought down on the tangs from above causing heat and pressure to be distributed on the commutator body.
A major disadvantage of such a commutator has been that the winding wire cannot be readily welded or hot staked to tangs of the commutator segment because the heat and pressure required to make a good joint has caused distortion of the low temperature-softening moulding material which makes up the base.
As a result it has been preferable to use low temperature wire grades which can be readily soldered to the commutator tangs. This however places a limitation on the application of the commutator. It could not be easily used when high temperature winding wire is to be used.
This invention aims to provide a commutator design which allows the use of a low cost assembled commutator with high temperature wire welded to the tangs without any danger of damage to the commutator base.